The main area of application for an apparatus or method based on the invention is, in particular, sensitive and rapid analysis of chemical substances and, in particular, rapid and reliable assessment of the toxicity of unknown substances.
Previous methods of analysis of the toxicity of chemical substances are usually based on classical, typically wet-chemical, analyses and on spectroscopic and physicochemical measurement methods. Such methods of analysis usually have a comparatively complex apparatus design, require long analysis times and/or often have unsatisfactory detection sensitivity. In the case of conventional methods of analysis, the detection threshold for the substance or mixture of substances to be analyzed is often comparatively high, in particular.
In first approaches, the prior art also uses neural networks for analyzing particularly the toxicity of chemical substances. In this context, the neural activity of the neural network is usually detected using the technique of “patch clamping” or extracellular microelectrodes. Patch clamping involves invasive, intracellular signal derivation, while extracellular microelectrodes use a noninvasive method of detection with extracellular signal derivation. In both cases, an external measuring amplifier is connected to the detection electrodes and accords the time profile of the corresponding electrical voltage. The external measuring amplifier thus delivers voltage/time signal profiles—“transients”—for neural signals, which are subsequently evaluated.
To increase the yield of suitable nerve cells with which correct contact has been made and also the statistical meaningfulness, the use of regularly arranged sensors is known. In this context, reference is made particularly to the publication by Oka et al. “A new planar multielectrode array for extracellular recording: Application to hippocampal acute slice” in Journal of Neuroscience Methods 93 (1999), pages 61-67, Elsevier.
Although such sensor arrangements allow resolved-time signal detection of individual neurons on the sensor, they have only limited use for reliably and rapidly assessing particularly the toxicity of unknown substances.